Dynamic Mechanical Analyzer (DMA)

A Dynamic Mechanical Analyzer is used to measure mechanical and viscoelastic properties of materials.

Dynamic Mechanical Analysis (DMA)

Determine the force and displacement amplitudes as well as phase shifts with the dynamic mechanical analyzer. The unparalleled versatility o...

Determine the force and displacement amplitudes as well as phase shifts with the dynamic mechanical analyzer. The unparalleled versatility of the DMA 1 allows applications to be performed in the optimum measurement configuration. The DMA 1 is easy to set up, whether for conventional DMA analyses, experiments using static forces or measurements in liquids.

Dynamic mechanical analysis (DMA) is an important technique used to measure the mechanical and viscoelastic properties of materials such as thermoplastics, thermosets, elastomers, ceramics and metals. In a Dynamic Mechanical Analyzer, the sample is subjected to a periodic stress in one of several different modes of deformation. The force and displacement amplitudes and phase shift are analyzed as a function of temperature, time and frequency.

DMA provides quantitative and qualitative information that is of great value to process and application engineers, materials research scientists and chemists, such as:

Young’s modulus and shear modulus

Damping characteristics and viscoelastic behavior

Polymer structure and morphology

Flow and relaxation behavior

Dynamic Mechanical Analyzer DMA/SDTA 1+

The operating principles of the DMA/SDTA are in many respects very different to those of the current generation of conventional DMA instruments. The massively built stand results in the system having an intrinsic resonance frequency of about 1500 Hz, well above the measurement frequencies used. The sample itself is fixed directly to the force sensor so the force actually applied to the sample is measured. This technique was developed at the Institute of Dynamic Material Testing, University of Ulm, Germany, where it has been in successful use for several years and has undergone continuous development. The modulus is calculated from the ratio of force to displacement multiplied by a geometry factor given by the sample dimensions. The modulus can be determined with great accuracy because both force and displacement are measured. The fixed and moving parts can be adjusted via a three-dimensional alignment device so that the force is applied at an angle of exactly 90° to the sample and no errors due to transverse forces occur.

Dynamic Mechanical Analyzer DMA 1

The unparalleled versatility of the DMA allows applications to be performed in the optimum measurement configuration. The DMA is quick and easy to set up, whether for conventional DMA analyses, experiments using static forces or measurements in liquids.

Measurements at controlled relative humidity

The Humidity option consists of a special humidity chamber, a circulating heating bath and a humidity generator. It allows you to perform measurements under optimum conditions in every deformation mode. Special readjustment is not necessary after installing the humidity chamber.

Measurements with static forces

Besides the dynamic mode, the DMA permits measurements to be per- formed using static forces (TMA mode). All the deformation modes avail- able for DMA can be used.

Measurements in liquids

The Fluid Bath option allows you to perform DMA or TMA experiments in liquids using all the standard deformation modes. The entire sample holder and sample is immersed in the liquid. The Fluid Bath option consists of a special immersion bath and external temperature control using a circulating heating bath or chiller.

DMA is an important technique used to measure the mechanical and viscoelastic properties of materials such as thermoplastics, thermosets, elastomers, ceramics and metals.

In DMA, the sample is subjected to a periodic stress in one of several different modes of deformation (bending, tension, shear and compression).

Modulus as a function of time or temperature is measured and provides information on phase transitions.

DMA technology is the perfect solution when maximum accuracy is required and the material has to be characterized over a wide range of stiffness and/or frequency. In addition, DMA technology is extremely versatile and therefore, DMA can characterize materials even in liquids or at specific relative humidity levels.

Wide Frequency Range

The frequency range has been extended to the kHz region for the first time ever in a DMA instrument. In the shear mode, six decades are available. The region above 1 Hz is particularly interesting because it means that measuring times can be kept to a minimum.

Flexible positioning of the measuring head

The Measuring Head can be placed in the most convenient position for mounting sample holders and clamping samples. Afterward, it is set to the optimum position for measurement in the particular deformation mode. The orientation of the Measuring Head is automatically detected.

Ergonomic design with large touchscreen

Touchscreen of the DMA 1 The touchscreen allows visual contact with the instrument, even from a distance and has two important functions:

It displays the current spring displacement when mounting the sample holder

It monitors the sinusoidal excitation function.

TMA measurements

Measurements with static forces - besides the dynamic mode, the DMA 1 permits measurements to be performed using static forces (TMA mode). All the deformation modes available for DMA can be used.

DMA measurements can be performed under very different conditions to characterize the mechanical properties of materials. A great deal of information about a sample is obtained when the temperature, frequency or displacement amplitude is varied. The mechanical properties of composites or anisotropic materials can only be fully described by varying the direction of the deformation measurement or by using other measurement modes. This article discusses a number of typical examples.

The glass transition of semicrystalline polymers is often weak and difficult to measure by DSC. In this article, we show how a glass transition step of less than 0.1 J/g·K can be reproducibly determined using the DSC. The sample investigated was isotactic polypropylene (iPP) with a degree of crystallinity of 50%.

The TGA-GC/MS system can be used to investigate the composition of unknown samples. This is done by installing the IST16 storage interface between the TGA and the GC/MS. The interface allows up to 16 evolved gas samples to be stored at different furnace temperatures during the TGA measurement. The gas samples are analyzed and identified by GC/MS when the TGA analysis is finished. This article describes how a black polymer granule was characterized using this technique.

The mechanical properties of polymer-metal adhesive joints were studied as a function of the thickness of the adhesive layer using DMA. The glass transition temperature and the effective crosslinking density were evaluated from the shear modulus measurement curves. The results show that both quantities are strongly dependent on the thickness of the polymer layer. This is due to the formation of an interphase in the contact region of polymer and metal. The properties of the interphase depend on the metal used.

DMA measurements provide many different possibilities for characterizing materials. This article shows how DMA in combination with other thermal analysis techniques can be used to comprehensively characterize materials using different polymers as examples.measurement modes. This article discusses a number of typical examples.

Safety is an important aspect in process development in the chemical industry. This article, describes how reaction calorimetry and DSC can be used to quickly assess the thermal hazard potential of chemicals and chemical reactions.

In many applications, such as in cables or seals, rubber blends must possess both excellent mechanical properties and good flame-resistant properties. This article shows how flame resistance can be easily determined by TGA measurements and how the combination of mechanical and thermogravimetric measurements can be employed to optimize properties.

Photopolymerization is nowadays a widely used process. Systems are used for medical applications, for example in dentistry, for adhesive applications, in coating technology, and quite recently for 3D printing [1]. This article describes how the curing behavior of a two-component UV-curing sample can be investigated.

Many different sorts of lipstick and mascara are nowadays available. The most important characteristics of these products are that the effect lasts a long time, that the products are easy to apply and easy to remove, and that they are physically and chemically stable and do not irritate the skin. The waxes and oils in lipstick are responsible for ease of application; carbon black is often used as pigment in mascara. Thermal analysis techniques allow the quality of these types of cosmetic products to be easily checked.

Tricalcium phosphate (TCP) is one of the main constituents of bone replacement materials which find wide use in medical and dental applications for bone grafting and for implants. This article shows how TGA/DSC and TMA can be used to investigate the synthesis of tricalcium phosphate and to determine the transition temperatures of different TCP polymorphs.

When polymeric binders are used in paints with hydrophilic pigments such as titanium oxide, the pigments must be treated beforehand with polymers that are compatible with the binder. Otherwise, large agglomerates can form due to poor adhesion between the binder and the particles. This can lead to brittle films and fractures in the paint coating. This article shows how TGA and DSC can be used to determine important properties of the coating using titanium dioxide as an example.

For many practical applications, it is important to be able to quickly and reliably identify polymers. This article describes how semicrystalline polymers can be identified by measuring their melting points using DSC.

A thermobalance coupled to a suitable Evolved Gas Analysis (EGA) system allows qualitative information to be obtained about the gaseous reaction or decomposition products formed in a TGA experiment in addition to purely quantitative information about mass changes. This new series of articles discusses the various measurement techniques that METTLER TOLEDO offers for such analyses.

The fluid bath DMA 1 option allows the influence of swelling on the dynamic mechanical properties of a sample to be measured in the temperature range 0 to 200 °C. This means that deformation conditions of components that are in direct contact with fluids can be simulated (for example drive or timing belts that permanently run in motor oil).

Crystalline pharmaceutical substances often decompose immediately before or during melting. To determine the glass transition temperature, the substance must be melted and then cooled as rapidly as possible so that decomposition and crystallization do not occur. In many cases, the heating and cooling rates of conventional DSCs are not high enough for this purpose. The METTLER TOLEDO Flash DSC however offers new possibilities. This is illustrated in this article using prednisolone as an example.

The interpretation and quantitative evaluation of thermal analysis measurement curves is difficult when several effects take place simultaneously. A number of methods are available that can be used to separate overlapping effects and analyze them individually afterward. Using suitable examples, we discuss strategies for DSC curves. A second article to be published in the next UserCom will cover TGA applications.

The shelf life of a packaged product, for example in the food sector, is often strongly influenced by the properties of the product packaging. An important factor here is the permeability of the product packaging toward water vapor. The ProUmid SPS and Vsorp sorption test systems in combination with special sample holders allow the transmission rate of water vapor through the packaging and the sorption rate of the packaged products to be determined experimentally.

TGA experiments in combination with a suitable evolved gas analysis (EGA) technique not only provide quantitative information about the change in mass of a sample but also qualitative information about the gaseous reaction or decomposition products that are evolved. In this series of articles, we will discuss the possibilities that METTLER TOLEDO offer.

DSC measurements can be performed up to about 700 °C using conventional DSC instruments. If higher temperatures are required, DSC curves can be measured up to 1600 °C using the TGA/DSC. This article compares DSC and TGA/DSC measurements and discusses how quantitative calorimetric measurements are possible in the high temperature region.

The first measurements of the thermal conductivity of powders [1] showed that powders can be an interesting alternative to vacuum systems for achieving good thermal insulation. Currently powders of different materials (ceramics or polymers) are used in packaging or for building insulation. On the other hand, the low thermal conductivity of powders entails serious risks in the production and manipulation of energetic powders intended for pyrotechnics or explosives. Knowledge of the thermal conductivity of powders is therefore crucial to avoid spontaneous ignition.

High demands are nowadays put on packaging materials. For example, depending on the application field, the materials must provide optimum barrier properties toward water vapor, oxygen or odorants. In addition, there are requirements regarding tear resistance, transparency and compatibility with the contents of the packaging. In this article, we show how the water vapor transmission rate of materials can be determined using a sorption test system.

The interpretation and evaluation of thermal analysis measurement curves is difficult when several effects take place simultaneously. A number of methods are available that can be used to separate overlapping effects and analyze them individually afterward. In this article, we discuss strategies for TGA curves using suitable examples.

Knowledge of the polymorphic forms of an active substance is very important, especially in the pharmaceutical industry. In this article, we show how previously unknown polymorphs of menthol can be identified and characterized by Flash DSC.

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